Direct fluid radioimmune assays using solid phase antibodies and iodinated haptens are being developed. Such systems are unaffected by lipoprotein, hemoglobin or smaller interfering substances. The syntheses of appropriate radioligands and antibody-matrix conjugates for such assays form the body of this Proposal. A specific antiserum to phencyclidine is to be used for soluble component and solid phase assays. Immunoradiometric assays with non-isotope labeled IgG will be pursued separately.